It may be common that you are seeing spaces in an extracted value in validation module because the OCRing is detecting a space in the extracted text.

For Example:

In a document Document_number we can have a space in 54 58,40.



To take care of above all you need to do is to add Format Extraction plugin in Extraction Module after all plugins and turn the value of that plugin to ON. After that you need to go to the respective index field and create a rule which will replace all spaces with EMPTY: